URINARY POSITIONING II

Functions of the Urinary System

Functions of the Urinary System

1. Removes waste from the blood

2. Maintains electrolyte balance

-Effect hydration, blood pH & muscle/nerve

function

3. Effects blood pressure

The kidney regulates

key electrolytes and helps regulate blood

pressure.

Water

Increased Antidiuretic hormone (ADH) causes water
reabsorption in renal tubules  of the kidneys.  Decreased levels increase urine production.

Sodium Regulation

ADH and aldosterone regulate osmolarity
(amount of solute per  unit volume of water in body). 
 Increased ADH decreases sodium concentration and aldosterone
increases sodium concentrations during hyponatremia.

Potassium

Aldosterone produced by the adrenal gland regulates
potassium which is necessary for proper muscle function. 

  Hyperkalemia (high serum potassium) causes the release of
  aldosterone which causes excretion of potassium by the kidneys, thus lowering serum potassium.

Blood Pressure

Low blood pressure is sensed by the kidneys
   that then produce renin in the arterioles that then produces angiotensin II that increases blood pressure.

Basic Physiology of the Kidneys

Filtration

reabsorption

secretion

- Takes place in renal corpuscle

  - Water, electrolytes, sugars, amino acids, pass from blood to glomelular capsule as filtrate

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- Occurs in renal tubule

  - Some useful substances returned to blood (electrolytes, water etc.)

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- Renal tubules secrete uric acid and ammonia etc.

The Nephron

Functional units of the kidneys

Consists of:

1. Renal Corpuscle  - Contains  Glomerulus & Glomerular Capsule (Bowman’s Capsule)

2. Renal Tubule

The Kidney

• Retroperitoneal

• Left is longer and more narrow than right

• Upper poles more medial and posterior than lower poles

The Kidney- anatomy

• Hilum

Notch in kidneys where blood vessels, lymph vessels, nerves and ureters enter kidney.

The Kidney- anatomy

Renal Sinus

fat filled space surrounding the renal pelvis.

the kidney anatomy

• Renal Medulla

Contain collecting tubes that drain fluid from renal tubules.

the kidney anatomy

• Renal Cortex

Outer portion of kidney that contains the nephrons (functional units of kidneys) consisting of  1. (A) glomeular capsule (Bowman’s Capsule) and (B) Glomeuli – Capillaries that filter the blood and 2. Renal tuble (passes fluid from the renal pyramids to the renal pelvis)

the kidney anatomy

• • Renal Pyramids

Renal columns – Extensions of cortex into renal pyramids that serve to anchor the cortex.

the kidney anatomy

Calyces

4-13 minor/2-3 major

– collect urine from renal pyramids and transfers to renal pelvis.

the kidney secretes…

1 – 2 liters of urine per day

Ureters

• length

• location

• function

• enter

•10 – 12 inches in length

• Retroperitoneal

• Function by perisatalsis

• Enter on posteriolateral surface of
   bladder (trigone)

The Urethra

length male/female

•1.5 inches in females (1 inch anterior to vaginal opening)

• 7 – 8 inches in male (travels through prostate)

The Bladder & Prostate

• location

• function

• how much fluid does it hold

• how is it imaged

•Prostate inferior to bladder

• Posterior to pubic symphysis

• Can encroach on urethra (BPH)

• Maintains viability or motility of sperm

• Bladder anterior to rectum and vaginal canal

• Bladder holds max. of 500 ml of fluid

• The prostate is commonly imaged with
   transrectal ultrasound

Types of Urinary Studies

antegrade

- Bolus injection nephrotomography

- Infusion Nephrotomography

- Intravenous Urography (IVU)

- Pyelography

Types of Urinary Studies

retrograde

- Retrograde Urography

- Cystoureterography

- Cystourethrography

Patient Preparation - IVU

• Low residue diet 1 – 2 days prior to exam

• Light evening meal

• Laxative

• Well hydrated

• NPO after midnight

Patient Preparation - IVU

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bun

creatinine

+3 more

• BUN (8 – 25 mg/dl)

• Creatinine (.6 – 1.5 mg/dl)

glomerlular filtration (GFR) 90-120

(below 60 is compromised function)

diabetic history (glucophage)

HX of heart disease, allergic asthma, current medications

CONTRAST HISTORY

1920’s

1950’s

1985

Serendipitous discovery of the unique x-ray absorption properties of iodine during treatment of syphilis

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First clinically usable media introduced!

All were considered ionic, high-osmolar contrast media

(HOCM)

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FDA approves use of nonionic, low-osmolar contrast media (LOCM)

Ionic Contrast Media

molecules must:

contain:

also known as:

osmolality:

high incidence:

• Molecules must disassociate

– Contain iodine, anions and cations that may
   interact with CNS

• Also known as High-Osmolality Contrast

Media (HOCM)

– Osmolality 1000-2000 mOsm/kgH20

– High incidence of reactions and complications as

compared to Low-Osmolality

Non-Ionic CM

also known as

media

osmolality

does NOT

cost

x

x

Also known as Low-Osmolality Contrast

   Media (LOCM)

– osmolality 290-860 mOsm/kgH20

• Does not disassociate into ions

• Higher cost

• Reduced complications
• pH range 5.5-7.4

Ionic Monomer

•  May be ionic monomers (one
   iodinated benzene ring) or

   dimer  (2 linked benzene rings)

• Ions may interact with CNS

•  Contain carboxyl  group molecule

    to achieve high water solubility

Nonionic Dimer

•May also be monomers (one
   iodinated benzene ring) or

   dimer  (2 linked benzene rings)

•  No ions to interact with CNS

• Contain no carboxyl group, but have
  several hydroxyl  groups per molecule
  to achieve water solubility

Elimination of the carboxyl group

---

Nonionics also have

and the ions result in less  reactions

from nonionic iodinated contrast media. 

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lower osmolality (3:1)  than ionic compounds (3:2)

Non-Ionic CM

viscosity

Viscosity is higher in non-ionic contrast

-Viscosity of water is 1 centipoise (cps)

-Viscosity of blood hematocrit 40%= 3-4 cps

– Decreased by warming

• Optiray® 320

25° C = 9.9 cps

37° C = 5.8 cps

JCAHO no longer recommends the use of

warmer units due to possible infection control

Contrast Agents - IVU

Reactions are related to:

All urinary studies use water soluble iodinated

contrast (50% – 70% iodine)  and may cause
adverse reactions in the body.

1. Osmolality

2. Ionic Vs nonionic structure

3. Viscosity

Signs of Allergic Reactions

rule of 5

Most reaction occur within 5” of injection

Rule of  Five – Most reactions occur within  5”

of injection.  These only occur in 5% of patients and

 only 5% of those are life-threatening.

Reaction of Symptoms

• Increased pulse rate

• Pallor

•Cool, clammy skin

• Urticaria

• Dyspnea

• Pharyngeal constriction

• Fall in BP of 30 mm or more below baseline

   may indicate an anaphylactic reaction

Early (Mild) Signs

Late Signs (Serious)

•Restlessness 

• Urticaria

---

•Pharyngeal constriction

•Arrhythmias

•Dramatic fall in BP

Iodinated CM Reactions

Cardiopulmonary Effects

• Pulmonary edema in preexisting heart

  disease

• Increased cardiac failure especially right-sided

  failure

• RBCs shrink due to osmotic gradient

– Rigid RBCs may not pass through small    

   capillaries resulting in tissue anoxia

Iodinated CM Reactions

Renal effects

– Osmotic diuresis

– Loss of potassium, calcium, phosphorus,

   urea, uric acid, magnesium, water and

   sodium

– Dehydration can occur

– Possible nephrotoxicity

CONTRAST-INDUCED NEPHROTOXICITY

• 98% of all iodinated media is eliminated by kidneys

• Renal blood flow first increases then decreases for several hours

CONTRAST-INDUCED NEPHROTOXICITY

By definition is when there is:

•A sudden, significant worsening of renal

  function after receiving intravascular

  contrast.

• 20-50% rise in baseline creatinine

  or a rise in serum creatinine of at least

  0.5 mg/dL within 48 hours.

Iodinated CM Reactions

Anaphylactoid Reactions

• Mild to severe

– 94% of severe and fatal reactions occur with in 20 minutes of injection

– 60% within 5 minutes

– Delayed reactions may occur days or weeks after injection but are usually mild

May be prevented by:

– Premedicate with steroids and antihistamines if known allergy to contrast or high risk (asthma,multiple allergies)

– Emergency medication must be readily available

Incidents of contrast Side Effects

Overall Complications

Ionic = 5%, Non-ionic = 1%

Death

Ionic

1:40,000 – 1:70,000

Non-ionic

1:200,000

Nephrotoxicity is 10% (higher in diabetes
mellulitis and dehydration), usually resolves
spontaneously

Response to Reactions

1.Call for help

2.Open/obtain drug box

3.Obtain patient vitals

Patient Preparation for IVU

•Low residue diet 1-2 days prior

•Light evening meal day before exam

•Laxative

•Well hydrated

•NPO after midnight

Equipment - IVU

•Tomographic Table- CR equipment

• Markers

•14 X 17 and/or 10 X 12 IR’s with analog studies

• Compression band – Placed at level of ASIS

• Emergency drug cart or drug box

A doctor (preferably the radiologist must be

immediately available)

Radiation Protection

• Males shielded with lead below symphysis

  when possible – can use shadow shield

• Females hard to shield

• Good collimation is best protection

IVU - exposure

at the end of expiration

Intravenous Urography

Abdominal masses

 Renal cysts or tumors

  Pyelonephritis

Hydronephrosis

Evaluation of trauma to kidneys

Post-operative kidney function

Renal hypertension

Intravenous Urography

CONTRADICTIONS

Renal failure

Previous allergic reaction with non-ionic contrast

(in some cases patient may be pre-medicated)

Anuria

Non-Ionic Contrast is Recommended for:

• Elderly patients

• Patients with asthma

• Patients with a previous contrast reaction

• Patients with cardiovascular arrhythmias

•Patients with a slight increase in BUN or

  Creatinine

• Patients with sickle cell anemia

• Patients with diabetes mellitus

• Multiple myeloma patients

Preliminary Steps for the IVU

•Scout film

• Foot board

• Pillow under knees

 Explain procedure/ get hx

Contrast Administration

•30 – 100 cc  for adult (1 cc per/lb. up to max. of
  150 cc)

• Amount in children depends on weight and age

• Sex of patient must be considered

• Nephrogram phase occurs first (within in first 5”)

• Pelvicalyceal shows up within 2 – 8 minutes

Common Projections

Normally AP projections ranging from 3” – 20” (minutes)

Routine Projections include a

Scout

Tomograms of kidneys

AP
 Both obliques

Upright post-void.

IVU

Supplemental Positions

•Trendelenberg

• Prone Position

•Lateral Position

IVU

_ x _

AP Projection

CR

SS

14 X 17 IR

Position of the Part:

• Patient supine

•MSP centered to table

Central Ray:

• Centered to the midline at the iliac crests

(images must show kidneys, ureters, bladder)

Structures Shown:

• Kidneys, ureters, bladder

• Short-scale contrast (80 – 85 kVp used)

AP Oblique Projections

RPO and LPO Positions

POS

CR

SS

14 X 17 IR

Position of the Part:

• Patient supine

• MCP forms 30° angle to IR

• Center IR to iliac crests

Central Ray:

• 2” lateral to the midline on the elevated side

• Centered at the iliac crestsStructures Shown:

• Kidneys, ureters, bladder

• Kidney closest to IR is perpendicular to IR,

  kidney farther from IR will be parallel to IR

Nephrotomography/Nephrourography

Bolus Nephrotomography

EXAM PROCEDURE

•Demonstrates renal parenchyma

• Indications include evaluation of renal

   hypertension, cysts and tumors

•Scout film

•Large bolus injection

• AP projection of abdomen during arterial phase

• Tomographic images during nephrotic phase

   (within 5 minutes of injection)

• Tomographic section in posterior 1/3^rd of

   abdomen (commonly 9, 10, 11 cm)

Nephrogram Pathology

Decreased uptake during nephrogram phase at 1 minute
tomogram and small right kidney indicates right renal  arterial stenosis.

Percutaneous Antegrade Pyelography

Direct  stick of the kidney with injection of

positive contrast into renal pelvis

• Used to evaluate hydronephrosis

• Largely replaced by ultrasound

Retrograde Urography

Direct catherization of ureters with a

ureteroscope with injection of positive contrast

to visualize the bladder ureters and renal pelvis

•Used in cases of renal insufficiency/allergies

  to iodine

• Shows structure well, but little about function

Retrograde Urography

Procedure

Operative procedure requiring  surgical asepsis

•Patient is supine, knees in flexed (lithotomy
   position in stirrups)

• Cystoscope inserted through urethra into bladder

• Catheter inserted into ureters

• Colored dye injected IV to check renal function

  Contrast injected to visualize renal pelvis/ureters

Retrograde Urography

images

supplemental images

Three images obtained (14X17, centered at L -3):

   1. AP scout

   2. Pyelogram image – head of table lowered

       10 - 15°

   3. Ureterogram image – head of table elevated

       35 - 40°

Supplemental Images: RPO/LPO positions

Cystography

Radiographic visualization of the bladder

using positive contrast media

Cystoureterography

Shows bladder & lower ureters

Cystourethrography

Shows bladder and urethra

Cystography

Indications

•Vesicoureteral reflux

• UTI

• Urethral strictures

• Bladder trauma

• Neurogenic bladder

Cystography

Preparation

•Table covered with radiolucent plastic sheet

• Urine collection receptacle

• Perineal care prior to exam

• Proper aseptic technique

• Catherization of patient or use of acorn plug

   for female patients

Cystography

Procedure

•Contrast is injected into the bladder

• Routine projections include AP axial, both

  obliques and lateral

• Chassard-Lapine projection may be used

   supplementally to show posterior bladder &

   lower ureters

Cystography

AP Axial Projection

POS

CR

SS

10 X 12 IR lengthwise

Position of the Part:

• Patient supine

• MSP centered to grid

• Center IR 2 inches above pubic symphysis

  (at the pubic symphysis for voiding studies)

• Expose at end of respiration

Central Ray:

• Angled 10 - 15° caudal & centered to IR

Structures Shown:

Bladder

Lower ureters may be shown when reflux is

present

AP Oblique Projection

RPO or LPO Position

IR

POS

CR

SS

10 X 12 IR lengthwise

Position of the Part:

• Patient supine & rotated 40 - 60°

• Abduct upper thigh away from bladder

• Center IR 2 inches above pubic symphysis &

  2 inches medial to upper ASIS

Central Ray:

Perpendicular & centered to IR

Note: 10 ° caudal angle when bladder neck

and urethra are areas of interest

Structures Shown:

Bladder

Ureters when reflux present

Lateral Projection

POS

CR

SS

Position of the Part:

• Patient in lateral recumbent

• MCP centered to grid

• IR centered 2 inches above pubic symphysis

Central Ray:

Perpendicular and centered to grid

Structures Shown:

Anterior, posterior and base of bladder walls

Male Cystourethrography

AP Oblique Projection

IR

POS
CR

10 X 12 LW

Part Position:

• Patient supine & rotated 35 - 40° for entire study

• IR centered to the superior border of pubic

  symphysis

• Patient’s elevated thigh extended

• Patient’s lower leg flexed

Central Ray: Perpendicular & centered to the IR

at pubic symphysis

Male Cystourethrography

AP Oblique Projection

Procedure

SS

•The patient injected with urethral syringe

    loaded with a Brodney clamp

• Penis extended along soft tissue of leg

• Exposures taken during filling and voiding

Structures Shown:

Bladder and urethra

Female Cystourethrography

AP Projection

IR

CR

PROCEDURE

SS

Position of the Part:

• Patient supine

CENTRAL RAY

•Centered at the superior border of the

   pubic symphysis

• Angled  5° caudal

Procedure:

• Perform endoscopy

• Catherize bladder & drain, remove catheter

• Syringe with soft-rubber acorn used to inject

  contrast

• images taken during filling and voiding

• AP and oblique projections

  (35 - 40°) also be required

Structures Shown:

Bladder and urethra

Female Cystourethrography

Metallic Bead Chain Method

Procedure:

Images Show:

Shows abnormalities associated with stress incontinence

•PROCEDURE

Chain threaded into urethral orfice

• Foley inserted and bladder drained

• Contrast instilled and catheter removed

• AP and lateral images taken at rest and

  during straining

•IMAGES SHOWN

Anatomic bladder changes (shape & position)

• Position of bladder floor

• Position of proximal urethral orfice

• Angle of inclination of urethra